On the page you will see the known recipes applicable to Crafting & Gathering - 5e Player Reference Handbook . The information is colour-coded to be a little easier to read - and any line with an icon such as ‘Aberration’, ‘Stinger (DC15 Aberration)’, or ‘Heliana’s Guide to Monster Hunting’ - links to another page for more information.
Some of the things needed come from ‘Boss’ encounters found in books such as; Heliana’s Guide to Monster Hunting, or Motes of the Divine - Horror Filled Monster Hunts. Otherwise, anything not tagged in the ‘Monster Hunt Book & Hunt’ can be freely made!
… all providing you have the coin, time and a will do collect powerful Essences from slain foes!